Devyn Sharpe

Overview

WestProp VMS is an internal enterprise platform used to run procurement, finance, HR, and operational workflows across the group. It replaces spreadsheet- and email-driven processes with explicit workflows, enforced permissions, and auditable records. Built and owned end-to-end in a de facto internal CTO role, the system provides executives with real-time visibility while enabling non-technical teams to operate safely within defined controls.

System Architecture

• Frontend: React + TypeScript with shared internal components for data tables, approval flows, multi-step forms, and status indicators. Designed for data-heavy screens and long-running approval processes.
• Backend (API-first): Node.js + TypeScript with explicit workflow logic modelling real business states (draft, submitted, approved, rejected, paid). Business rules live in services, not controllers.
• Data modelling: Structured relational models for suppliers, RFQs, requisitions, invoices, payments, staff, leave, and performance cycles. Financial records are append-only; historical states are preserved.
• Security: Role-based access control with enforced separation of duties (requesters, approvers, finance). All sensitive actions are attributed and logged.
• Integrations: Payment and accounting integrations, document storage with signed URLs, and optional facilities and access-control hooks.

Key Engineering Challenges

• Formalising real processes: Converting informal, people-driven workflows into deterministic systems without breaking how teams actually work.
• Approval flexibility: Supporting configurable approval chains while retaining full auditability.
• Financial safety: Preventing duplicate payments and out-of-policy approvals through invariant checks and idempotent operations.
• Usability: Designing flows where the safe action is the easy action for non-technical users.

Business & Technical Impact

• Approval cycles reduced from days to hours with clear visibility into bottlenecks.
• Audit preparation no longer requires reconstructing decisions from email threads.
• Lower operational risk through enforced controls and separation of duties.
• New modules added with minimal rework due to shared workflow and UI foundations.

Overview

A multi-tenant residents portal serving thousands of owners and tenants across multiple developments. Built end-to-end in a senior full-stack / CTO capacity, the platform provides secure self-service access to statements, levies, invoices, payments, subscriptions (utilities, Wi-Fi, solar, rentals), documents, maintenance requests, and development-wide communications.

Technical Architecture

• Frontend: React + TypeScript with reusable form, table, and document components. Optimised for large financial histories using memoisation, code-splitting, and virtualised lists.
• Backend: LoopBack 4 API providing a strongly-typed service layer with clear domain boundaries. REST endpoints are consumed via RTK Query for predictable data access, caching, and synchronisation.
• Payments: Stripe Elements and subscriptions with verified, idempotent webhooks. Background reconciliation ensures Stripe activity matches the internal ledger.
• Data layer: PostgreSQL with tenant-scoped relational models for developments, units, residents, invoices, ledger entries, and payments. Isolation enforced via scoped keys and RLS.
• Security: OAuth2 and password-based authentication with optional MFA. Fine-grained permission checks and access logging for sensitive data.
• Scalability: Stateless APIs behind a load balancer with background workers for billing and webhooks. New developments onboarded via configuration rather than code.

Key Engineering Challenges

• Financial correctness: Implementing a double-entry ledger to ensure full auditability of invoices, adjustments, and payments.
• Subscription lifecycles: Handling proration, retries, and failures without reconciliation drift.
• Multi-tenant safety: Strict isolation at every layer with tooling for migrations and backfills.
• Permissions: Mapping real-world roles to precise, enforced capabilities.
• Operational resilience: Retryable workflows, dead-letter queues, and structured logging.

Impact & Results

• Thousands of active users with consistent sub-second performance.
• Automated reconciliation reduced manual finance workload by over 80%.
• Zero cross-tenant data incidents and full audit readiness.
• New developments onboarded without application code changes.

Overview

Ellipsis Marine is a purpose-built operations platform for managing real-world maritime activity, replacing fragmented spreadsheets, chat threads, and paper logs with a single system of record. It supports vessels, charters, crew, maintenance, compliance, and financial tracking in a way that mirrors how marine operations actually run day to day.

System Architecture

• Frontend: React + TypeScript with data-dense operational views focused on current status, constraints, and next actions rather than dashboards for their own sake.
• Backend: Node.js + TypeScript API with domain-driven design. Business rules live in services and enforce valid state transitions for charters, maintenance, and compliance workflows.
• Data layer: Relational models aligned closely to real maritime entities, with explicit state machines and preserved historical records.
• Auth & permissions: Role-based access for owners, operators, crew, and administrators. Sensitive actions are logged and traceable.
• Scalability: Designed to support multiple vessels, operators, and mixed private and charter operating models without schema changes.

Core Domain Models

• Vessels: Specifications, equipment, capacity, and compliance status with full historical tracking.
• Charters: Time-based bookings with clear lifecycle states from planning through completion and settlement.
• Crew: Licensing, availability, and assignment validation against operational requirements.
• Maintenance & operations: Scheduled servicing, defect reporting, and operational readiness tracking.
• Financial records: Revenue and costs recorded non-destructively, with adjustments preserved rather than overwritten.

Key Engineering Challenges

• Modelling real operational constraints without allowing invalid or unsafe states.
• Designing workflows that remain usable under time pressure while still enforcing rules.
• Balancing flexibility for operators with long-term data integrity and auditability.

Impact & Outcomes

• Replaced fragmented tools with a single operational view across vessels and charters.
• Reduced operator error through enforced workflows and clear state visibility.
• Established a foundation capable of scaling across fleets while remaining auditable.